A positive-definite matrix is an important concept in linear algebra.

There are times when we perform calculations with the haversine in trigonometry.

He drew an equilateral triangle shape.

He is an expert in orthoepy, teaching pronunciation.

He made a model of a regular tetrahedron.

This orthophoto shows the details of the terrain very clearly.

His long talk is just like 'a hundred days of sermonizing without a fart.'

A positive-semidefinite matrix is one of the important concepts in linear algebra.

Kunminjōon is a book for teaching the correct pronunciation of Hangul.

A tesseract is a four-dimensional geometric shape.